There are a limited number of cattle parasite control products that can be used for treating cattle which are or may in future be used to produce milk for human consumption. This includes heifers that have not yet been joined (mated).
Many products have label instructions that state ‘DO NOT USE in dairy cattle which are producing or may in the future produce milk where the milk or milk products may be used for human consumption’. Note that veterinarians are not permitted to override these instructions with an off-label prescription. The milk from animals treated with these products can be used in soap-making or for rearing calves.
For an alternative to drench treatments of dairy cattle see also non-chemical worm control methods.
Commercial dairies should discuss parasite management options and alternative management techniques with their veterinarians and extension officers. The company you supply milk to will also have stringent requirements for the selection and application of parasite control products.
Other owners of dairy cattle and house cows should also discuss their individual situation with their veterinarian and extension officers. Implementing alternative parasite management options and management techniques will greatly assist in reducing the amount of parasite control products applied to the cow.
Dairy Australia provide useful animal husbandry and milk production resources on their website.
Figure 1. Fewer chemical actives can be used on cows producing milk for human consumption. Image courtesy Jody Burgess